1. Field of the Disclosure
The subject application relates generally to processing of metal ores or concentrates, and in particular to a process for separation of at least one metal sulfide from such ores or concentrates.
2. Description of the Related Art
Metallurgical processes are applied to metal ore deposits and such processes can be categorized into three general areas: leaching, solution concentration and purification, and metal recovery.
Such processes have been previously described. For example, U.S. Pat. No. 3,709,680 to Holmes et al. (1973) is directed to leaching a copper concentrate prepared by flotation using a hot concentrated caustic solution.
U.S. Pat. No. 3,911,078 to Nadkarni et al. (1975) is directed to a method for removing chemically bonded arsenic and antimony from copper sulfide ores.
U.S. Pat. No. 4,017,369 to Lindstrom (1977) is directed to the recovery of the antimony, arsenic, mercury and tin from alkaline leach solutions by electrowinning.
U.S. Pat. No. 4,051,220 to Coltrinari (1977) is directed to a process for treating mixed metal sulfides containing trivalent antimony sulfide. The process involves leaching with sodium sulfide to isolate copper sulfide as an insoluble solid. Following leaching, antimony and arsenic values are oxidized.
U.S. Pat. No. 5,137,640 to Poncha (1992) is directed to a process for reducing arsenic levels in a solution containing sulfuric acid, water, and arsenic acid by adding copper or a copper-containing compound to the solution to form dissolved copper arsenate, adding alkali solution to precipitate the copper arsenate and to neutralize arsenic and sulfuric acid.
U.S. Pat. No. 5,290,338 to Anderson et al. (1994) is directed to an antimony recovery process in which an antimony-containing material is leached in a solvent including elemental sulfur and caustic.
U.S. Pat. No. 5,750,019 to Olper (1998) is directed to a hydrometallurgical and electrochemical process for processing sulfur antimony ores and residues, the end products from which are electrolytic antimony and elemental sulfur.
Most of the economically significant base metal ore deposits worldwide contain mixed sulfides. Several types of mixed sulfide ores and concentrates may contain relatively large quantities of lead sulfide together with sulfides of other metals, such as copper, antimony and arsenic. Known metallurgical processes do not provide satisfactory metal sulfide separation from such ores and concentrates. It is desirable that certain metal sulfides be separated and recovered from ores and concentrates and converted, if necessary, to a form suitable for commercial sale, while other more deleterious elements (e.g. other metals/metal compounds) may be removed. Deleterious elements are understood to mean elements that are considered commercially deleterious and therefore, can vary widely depending on the commercial application. It is also desirable that the cost of separation of at least one metal sulfide and/or removing deleterious elements from the concentrate at or near the mine be kept low.
Accordingly, there is a need for an improved process for separation of at least one metal sulfide from a mixed sulfide ore or concentrate.